Not silly at all.
You can start out as a freewrite - but truth be told, not many of the freewriters stick with the 5 minutes. Many use the timer or the most dangerous writing app to get started and then, either keep going if the muse strikes them or edit and write a longer piece.
For the contest - make it as long or as short as it needs to be.
Thank you for asking!
Good to know. Thank you!